13T - Rear Differential Oil

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Darin Hull
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13T - Rear Differential Oil

Post by Darin Hull » Sat Apr 25, 2020 12:12 pm

Gentlemen,

I’ve read several of the previous forum threads on changing out the differential oil. This 13T hasn’t been driven in over 10 years which means what hasn’t leaked out has been sitting for a long time. I’d believe the advice would be to change the oil and not add to it but looking for suggestions from the brain trust.

Whether I tap an 1/8” hole and put in a new plug, or use a suction device, any guidance on the best way to prepare for the change since it won’t be driving? Heat gun, nothing just go get it, etc?

Saw some discussion on using 140w oil as a replacement. Any new comments on that front?

Thank you for your time,
Darin
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Re: 13T - Rear Differential Oil

Post by Mark Gregush » Sat Apr 25, 2020 12:28 pm

While I might suggest adding a drain on the 1916 up rear ends, I would be hesitant to do so on an early one. My suggestion would be suck as much out as you can, then fill with diesel, mineral spirits or kerosene, with the wheels off the ground run the car (don't forget to chock the front wheels). Let it soak then run again. Drain then repeat. Let sit over night so it has time to drain down and then remove all that you can. Fill with your choice of lubes to about 1" below the filler hole while still on the jacks run to circulate the lube. Take the car off the jacks, let the lube settle then check to adjust to proper level up or down.
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Re: 13T - Rear Differential Oil

Post by Oldav8tor » Sat Apr 25, 2020 1:00 pm

Hmmm... If you're not going to drive it does that mean it does not run or you do not plan to start it? If so, some of Mark's advice (which is good) won't apply.

If you don't plan to drive it I don't know if it is absolutely necessary to remove the old oil at this time. You can dip something in the filler hole and get an idea what shape it's in. Regardless, I think it would be wise to try to spin the gears and such in the differential to coat them with oil. Same is true of the engine. Maybe jack the rear end up, take out the spark plugs and crank it for awhile. Hopefully someone who has been in your situation will chime in with advice.
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Re: 13T - Rear Differential Oil

Post by Erik Johnson » Sat Apr 25, 2020 1:02 pm

Depending on the mileage since the lube was last changed, it wouldn't bother me if it sat for ten years and just needs to be topped off. If you know what viscosity is currently in the rear-end, just add more until the level is 1.5 inches below the bottom of the fill plug.

The above is just my opinion so take it with a grain of salt.


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Re: 13T - Rear Differential Oil

Post by Darin Hull » Sat Apr 25, 2020 1:25 pm

To clarify, it hasn’t run in over ten years but I’m working my way to getting it back to drivable. Doesn’t crank either due to a variety of projects which are almost complete. So, the advice which necessitates driving won’t work for me at this point... hopefully, by the summer I’ll be there.

Darin

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Re: 13T - Rear Differential Oil

Post by Mark Gregush » Sat Apr 25, 2020 1:27 pm

Then if it were me I would be getting it running first then worry about the rear end. With unknown lube in the rear end, I would still do a flush and refill at a later date. Also, when you check the lube be watching for silver color, which could indicate the thrust washers are babbitt/white metal and are coming apart, unless you know it has bronze ones installed.
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Re: 13T - Rear Differential Oil

Post by John kuehn » Sat Apr 25, 2020 1:59 pm

Do you know any history about the rear end? Ever been rebuilt or? As far as changing the oil in it do as Mark G says and thin it down with diesel a couple of times or more and drain and redrain.
Then jack up the rear of the car and put the car in neutral. Then turn the rear end by hand and listen for any noise or clicking. Don’t know if you want to do this but that will give you an idea if something isn’t right.
If OK then fill with differential oil and you should be OK. Also check out the old thinner oil by straining it with fine screen wire or coarse cloth to see if you find any metal slivers and etc.
Hope this helps.

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Re: 13T - Rear Differential Oil

Post by Oldav8tor » Sat Apr 25, 2020 2:07 pm

If your goal is to get it running, my suggestion would be to pull the rear end and go thru it carefully. Babbitt thrust washers should be replaced with bronze and the condition of the axles, driveshaft, gears, Hyatt bearings, bushings, universal and such should be be determined. I would also suggest installing a Fun Products Modern Pinion Bearing in place of the original Hyatt. Floating safety hubs are an excellent way to relieve much of the strain on your axles and insure that if one does break, the wheel will stay on the car...

A friend of mine with a 1919 was recently towing his car in an attempt to start it. When he engaged the clutch a rear axle broke and the wheel fell off. Further examination showed that the axle must have had a crack for a long time that finally failed when extra force was applied. Opening the differential to replace the axle (he replaced both because the other showed scoring) he found babbitt thrust washers-another accident waiting to happen. He is now rebuilding it with new axles, floating safety hubs, etc., etc. If you plan to drive the car frequently then it's good to know the condition of the moving parts. My car had sat for at least 30 years when I got it. I went thru everything that moves on the car and now have a Model T that I trust explicitly. I'm not guessing about it's condition....I know! Just my two cents.
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Re: 13T - Rear Differential Oil

Post by TWrenn » Sat Apr 25, 2020 7:57 pm

If it's possibly (and quite probably) still got the original "tar like goop" in it as I've encountered in a couple of '12s and a '20, frankly no amount of diesel fuel and draining will clear it out adequately. This crap is almost like tar. IF that's what it's got in it, and you should be able
to tell with a good inspection thru the hole, and today there is all sorts of neat little optical devices you can attach to your smartphone to look at it, then really a "tear down" would be the best thing. Then you can inspect everything for wear anyway, and refill it with the so-called 600 oil you can get from Snyders or Langs. Just my two cents!!


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Re: 13T - Rear Differential Oil

Post by DHort » Sat Apr 25, 2020 8:50 pm

You could always put a light bulb under it for a while and then turn the rear wheels a bit to move it around. Then stick your finger in to see what is in there. Your best bet is to probably tear it apart anyway.


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Re: 13T - Rear Differential Oil

Post by Original Smith » Sun Apr 26, 2020 11:12 am

Stick a wire or a pipe cleaner through the filler plug to see what's in there. What ever you do, don't overfill it.


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Re: 13T - Rear Differential Oil

Post by Norman Kling » Sun Apr 26, 2020 11:24 am

I would agree with Oldav8tor. You need to go through the rear end before you take it on the road. So until you have the rest of the car ready to go, just leave the rear end as is. Then before you take it out for a ride, disassemble using the booklet "Rear Axle" published by the club which is a very good step by step guide for the amature mechanic. You really don't need any special tools except for pullers to get off the wheels and the pinion gear and bearing if necessary. Those thrust washers are very important because if they crumble, you will lose the gearing and brakes.
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Re: 13T - Rear Differential Oil

Post by TRDxB2 » Sun Apr 26, 2020 11:50 am

An answer to question on 140w gear LUB from this link http://www.mtfca.com/discus/messages/25 ... 1355711752
"December 13, 2012 - 10:13 am: I think the correct Lubriplate number is APG 140 rather than APW 140. The APG lube is specially formulated to cling to surfaces on devices that may not be used for longer periods of time and thus is ideal for us Model T folks who have to park their T for the winter months. I used to sell this on my web site but it has to be bought from bearing dealers and it was a constant negotiation and hassle so I stopped carrying it. APG 90 works best for Ruckstell rear end. Many folks confuse the viscosity issue by thinking that 600 Wt gear oil is thicker than 140 Wt gear lube. Gear oil is measured on a different scale than gear lube. I believe the lube that Lang is selling is APG which I should also mention is a GL4 type so it does not attack brass thrust washers in the rear end although I think that issue is over blown since those washers are far more likely to wear out before they are harmed by any additives. I run APG 140 in all my own T's and have used it for years. I like it but your mileage may vary."

An answer to question to refill or change: Once you decide on using 600 gear oil or 140 gear lube, your initial lubrication cost is the same, what you don't use will sit on the shelf till needed. Changing the oil is time and material cost is minimal. I would follow the advice given by others above to first determine the condition of whats left in the differential, may also give you some insight on the condition of the thrust plates, and proceed as necessary. Personally, I'd follow the recommendations to thoroughly clean out whats there because you have no idea how old or what lubrication was used prior to it sitting for 10 years.
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Re: 13T - Rear Differential Oil

Post by jiminbartow » Sun Apr 26, 2020 12:06 pm

I agree with earlier threads suggesting you pull the rear end, turn it on its’ side to empty out the 600wt oil, open it up dismantle it, clean it, inspect each part and replace old worn out seals, bearings and parts with new modern replacements and reassemble. I bought the 600wt. Differential oil used in mine from Snyder’s Antique Auto Parts. By rebuilding the differential, you know it will be safe. I would never drill a hole in an original ‘13 T pumpkin. If you plan on doing this again, invest in a suction pump. I invested in one on 1990 and only used it once. Have fun and stay safe. Jim Patrick

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Re: 13T - Rear Differential Oil

Post by Susanne » Sun Apr 26, 2020 2:53 pm

Don't drill it!!! A suction pump and a long enough hose will clear whats in the differential enough to change the oil out. The only other way to "Really" drain the oil out is to (a) dismount the differential from the car and drain what you can out of the fill hole, and if that's not enough, (b) split the pumpkin. It's not that hard, but it's time consuming.

As to viscosity? I remember reading somewhere that 600W is actually at 275 on the viscosity scale. The biggie with 600W (other than it's thickness) is that (being a steam service oil - really!) it does not attack brass or bronze, which is huge. It also has the thickness to cushion the gearing AND the "gooeyness" to travel to and adhere to your rear axle bearings. It also won't seep out of your rear wheel seals as readily as thinner oils will.

I also would not put a "thinner" or K1 in the diff without deciding to pull the axle and making sure all of that light petroleum is out of there... it doesn't take a lot of K1 to thin out heavy oils...


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Re: 13T - Rear Differential Oil

Post by jiminbartow » Sun Apr 26, 2020 11:45 pm

Susanne made a great point. The most important reason for having such a thick oil as the 600wt, is so that it will stay in the pumpkin and not seep past the seals on each side of the gearbox, into the shaft housings on each side of the pumpkin, for if the oil seeps out of the pumpkin over time, your differential will not be long for this world. It seems like you don’t know if the rear end has ever been rebuilt. That is all the more reason for you to do the rebuild so that you can be sure that it has new shaft seals on each side of the gearbox to keep the oil in the pumpkin. Jim Patrick


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Re: 13T - Rear Differential Oil

Post by Luxford » Mon Apr 27, 2020 2:43 am

Hi Darin,
Nice to hear from you again and that you are working on the T, as you may remember I mentioned when you inherited your Model T from your grandfather that I knew him very well.
I had Rodger stay at my house when he was in Australia on two occasions, and my wife and children stayed with him in his house when we were in Ohio.
We also saw him at several tours while in the USA.
Having known him very well I suggest you definitely remove the differential and completely overhaul it. It has been restored for many years, not sure exactly how long but probably as far back as the 1960's. Many members will recall that your grandparents were injured when the steering wheel and gear casing broke away from the column on one tour and it rolled over.
After all these years any old restoration should be thoroughly checked out to determine exactly what its condition internally it is in. I find it strange that some people in the past 10/20 years are extremely reluctant to do any major investigation into the condition of a Model T Ford they have that was previously owned by someone else. I could quote lots of cases ( and I"m sure others could also) where cars driven by new owners suffered major breakdowns due to the failure of the new owner taking the time to do a thorough check on the mechanics. Model T's are a simple piece of equipment experienced owners would not hesitate to disassemble at any time even on the road. If you wish to use a vehicle it has to be in good safe condition.
I find it scary when you ask an owner about a particular part of their Model T they can not supply any answer as to its condition. Fix it at home before use is a lot better than having it fail on the road, maybe causing extreme damage and then the time and cost of hauling it home and then doing a repair and replacing the broken parts.


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Re: 13T - Rear Differential Oil

Post by Darin Hull » Wed Apr 29, 2020 4:34 am

Thank you for the suggestions and I’m all on board for keeping safety as the priority. I remember the stories of that rollover accident well and would not care to repeat.

Speaking of checking for safety issues. I was inspecting the steering and took a look at the steering gear ball arm. I took off the ball cap (is that the right terminology?) and found two pieces of curved metal which were deliberately placed inside the caps and curved to form themselves over the spherical portion of the ball arm. Does the ball arm have a tendency to wear down with time which would mean these pieces were put in there to take out of of the play of the ball arm inside of the ball caps? Is the end of the ball arm usually have grease around it or is it unlubricated?

No matter the answer, I’d believe these two pieces should be replaced. Just curious if this is a normal temporary fix or if this is something which should be immediately repaired before driving the T even a mile.

Thank you for all the input and your time,
Darin


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Re: 13T - Rear Differential Oil

Post by jiminbartow » Wed Apr 29, 2020 1:08 pm

Yes. The cavity and ball do have a tendency to wear down, creating dangerous and unacceptable play in the ball and should be addressed ASAP, before driving the car. I have seen pitman arms so worn that the arm where the ball attached was to the point that the ball was in danger of breaking off, or the ball was in danger of pulling out of the tie rod hole.

APCO made a spring loaded ball cup that replaced the original unadjustable outer ball cap on the linkage attached to the pitman arm ball (www.modeltford.com. Part 2728APCO). A cup fit against the ball with tension provided by a spring with an adjustment screw that was used to apply tension to the cup to keep the ball from wobbling in the cavity. They make a larger size for the radius rod fork (www.modeltford.com. Part 2736APC). The Model T parts supply places (Lang’s, Snyder’s and others) have reproductions of these APCO parts. I have the original APCO parts on all of the ball joints of my T that were installed by the original owner probably in the 1930’s. They were encrusted with old oil, grease and dirt, so I know they were very old, but cleaned up like new during the restoration. They do a great job of removing the slop in all the ball joints. I highly recommend them. Jim Patrick

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Re: 13T - Rear Differential Oil

Post by Rosenfelder » Wed Apr 29, 2020 2:12 pm

If it has not already been mentioned, unless you have auxiliary brakes, the differential and drive line are critical parts of your stopping mechanism. Make sure that everything is in order. You wouldn't want something to fail in an emergency stop. It's one thing to just brake down, it's another to crash.


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Re: 13T - Rear Differential Oil

Post by Darin Hull » Sat Jul 18, 2020 9:33 pm

After some suggestions here, I’ll follow a short and long term solution. Short term, I bought a grease/oil suction tool and removed the old diff oil. Am putting new diff oil into it. Would this Lucas 85W-140 work or is there something I’m unaware of which would be mean disaster if I use this product? I bought this prior to seeing Lang’s 600w oil product. It wouldn’t be a big deal not to use it; however, if it’s just as good as anything else...

Long term, this winter, I would like to take the rear axle off, check the gearing, and make a more informed decision after an inspection. Will also need a new gasket because the diff has a decent leak.

Thank you for your time,
Darin
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Re: 13T - Rear Differential Oil

Post by D Stroud » Sun Jul 19, 2020 5:29 am

I don't know if the Lucas product is any better than any of the others, but we used to use 85w140 in the final drives on Cat dozers. I think it will be fine for a T rearend. JMHO. Dave
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Re: 13T - Rear Differential Oil

Post by Susanne » Sun Jul 19, 2020 1:43 pm

What's wrong with 600W? It's yellow metal compatible where the modern stuff usually isn't. It's readily available from the T vendors, and it's what was recommended for use by the people who designed it.


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Re: 13T - Rear Differential Oil

Post by Darin Hull » Sun Jul 19, 2020 2:29 pm

Susanne,

There’s nothing wrong with it. I bought this Lucas oil prior to realizing Lang’s offered 600w oil. I don’t want to waste the purchase if it works just as well as the 600w; however, I’d be more than happy to set it aside if the 600w is a much better choice. That’s why I asked, here to learn.

Darin

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Re: 13T - Rear Differential Oil

Post by Susanne » Sun Jul 19, 2020 6:49 pm

My dad used to run 85-140 in his differentials, and they always had a weird whine, there was a constant "drip" from the axle ends (not good for external brakes) and when you drive them you could feel a difference... I switched 2 of them (behind his back - s-h-h-h-h-h ;) ) to 600W. What I found was the rear ends quieted down, the leaks stopped, and they felt smoother...

Now I have gotten into "heated discussions" with others here on the board regarding Ruckstell axles... some say you need a light gear oil, not 600W... but both those cars had Ruckstells that were hard shifting, sticking, rough sounding rear ends... when I swapped them to the juice Ford said, they became easy shifting, smooth operating, quieter gearsets. Add to that - 600W (which is a steam oil designation, BTW) is about 275W in the current viscosity scale of oils... It is safe on yellow and white metals used in the rear ends... and is much thicker and "gooey-ier" than either of the common "gear oils" by a large margin.

I don't want to rehash this, as some people are pretty adamant over their rear end lube choices, just like motor oils, but it works for me (and worked for my dad), and has for some 35 years. I've yet to blow out a Rickstell or have a rear end failure running it. And some of my miles have been "ride hard and put away wet" daily driver miles.

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Re: 13T - Rear Differential Oil

Post by RustyFords » Mon Jul 20, 2020 10:49 am

When I read other's questions, I tend to ask myself, "What would I do if this were mine?"

In this case, if the condition of the rear end was unknown and I planned on driving it, it would get torn down to check the bearnings and thrust washers. With this approach, the condition of the current lubricant becomes moot.
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